Biocompatible and antibacterial poly(lactic acid)/cellulose nanofiber­silver nanoparticle biocomposites prepared via Pickering emulsion method.

Developing biocompatible and antibacterial materials with biodegradable polymers is an ideal strategy to improve public health problems and plastic pollution simultaneously. In the present study, novel biocompatible and antibacterial poly (L-lactic acid) (PLLA, coded as P)/TEMPO-oxidized cellulose nanofiber (TOCNF, coded as T)­silver nanoparticle (AgNP, coded as A) films were first developed. The core/shell PT Pickering emulsion was prepared by sonication treatment. The TOCNF shells with -COO-Na+ groups (∼1.5 mmol/g cellulose) were used as the support to in situ synthesize and immobilize AgNPs on the PT emulsion droplets. Silver nitrate (AgNO3) (1.5, 3.0, 4.5, and 6.0 mmol/g cellulose) was added to the PT emulsions. Then, ion-exchange reaction and hydrothermal reduction were conducted to form PTA (PTA1-PTA4) emulsions. After centrifugation to remove the excess Ag+, filtration, oven-drying, and hot-pressing, the PTA composite films were successfully prepared. The PTA3 film contained AgNPs 12.4 ± 2.8 nm in diameter and exhibited the highest antibacterial activities against the E. coli (85.2%) and S. aureus (80.1%) at 37 °C, where the initial bacterial suspension concentrations were approximately 2 × 108 CFU mL-1. Therefore, the biocompatible and antibacterial PTA3 film is a promising candidate for biomedical applications, in particular as an antibacterial bioactive packaging material.

Fucoxanthin decreases lipopolysaccharide-induced acute lung injury through the inhibition of RhoA activation and the NF-κB pathway.

Fucoxanthin is a natural pigment widely distributed in macroalgae and microalgae. An orange-colored xanthophyll, it has several bioactive effects, including anticancer, anti-obesity, oxidative stress reduction, and anti-inflammation. Acute lung injury (ALI) caused by acute infections or injurious stimuli to the lung tissues is a severe pulmonary inflammatory disease. To date, no evidence has shown ALI to be reduced by fucoxanthin through activation of Ras homolog family member A (RhoA) and the nuclear factor (NF)-κB pathway in lipopolysaccharide (LPS)-treated mice. Pretreatment with fucoxanthin inhibited histopathological changes in lung tissues and neutrophil infiltration into bronchoalveolar lavage fluid induced by LPS in ALI mice. Moreover, LPS-induced proinflammatory cytokine expression and neutrophil infiltration were inhibited by fucoxanthin in a concentration-dependent manner. Pretreatment of mice with fucoxanthin inhibited NF-κB phosphorylation and IκB degradation in the lungs of mice with LPS-induced ALI. We further found that phosphorylation of Akt and p38 mitogen-activated protein KINASE (MAPK) was inhibited by fucoxanthin. By contrast, the phosphorylation of extracellular signal-regulated kinase and c-Jun N-terminal kinase was not inhibited by fucoxanthin. Furthermore, we found that the activation of RhoA was inhibited by fucoxanthin in LPS-induced ALI. On the basis of these results, we propose that fucoxanthin disrupts the RhoA activation-mediated phosphorylation of Akt and p38 MAPK, leading to NF-κB activation in mice with LPS-induced ALI.

The effect of reduction on the properties of the regioselectively oxidized starch granules prepared by bromide-free oxidation system.

Development of intact oxidized starch granules by regioselective oxidation technology is of interest and provides a new research direction for oxidized starch. In this study, new sodium tetrahydridoborate (NaBH4)-treated oxidized starch (OS-BH4) granules were prepared by a one-pot method, where native corn starch (NS) granules were oxidized by 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)/sodium hypochlorite (NaClO) system followed by reduction with NaBH4. Oxidized starch (OS) granules without NaBH4 reduction were also prepared to investigate the effect of C6 aldehyde groups remained after TEMPO-mediated oxidation on properties of the granules. When degrees of oxidation were controlled to be not higher than 12%, both the OS and OS-BH4 granules had similar morphology to the NS granules with envelopes. Compared to the OS granules, except for lower pasting temperatures and dextrose equivalents, the OS-BH4 granules had higher molecular weights, degrees of polymerization (DP), peak viscosities, final viscosities, and swelling power. Difference of the properties was considered related to (1) repulsive forces formed between the C6 carboxylate groups, (2) C6 aldehyde groups with lower hydrophilicity than the C6 hydroxyl groups, and (3) some hemiacetal linkages formed between the C6 aldehyde groups and the hydroxyl groups. Furthermore, pregelatinized OS-BH4 granules were preliminarily prepared, which showed good swelling behavior with intact granular morphology in alkaline environment.

Observation of the Expression of Vascular Endothelial Growth Factor and the Potential Effect of Promoting Hair Growth Treated with Chinese Herbal BeauTop.

Despite minoxidil and finasteride already being approved by the Food and Drug Administration (FDA) for the treatment of hair loss, it is important to identify new and innovative treatments for hair loss, such as looking for a solution in Chinese herbal medicine. One such treatment to consider is BeauTop (BT), whose primary ingredients include Panax japonicus (T.Nees), C.A. Mey. (Araliaceae), Astragalus membranaceus (Fisch) Bunge (Fabaceae), Angelica sinensis (Oliv.) Diels (Apiaceae), Ligustrum lucidum W.T. Aiton (Oleaceae), Rehmannia glutinosa (Gaertn.) DC. (Plantaginaceae), and Eclipta prostrata (L.) L. (Compositae). The aim of this study was to evaluate whether BT can promote hair growth in C57BL/6 mice and to investigate hair coverage, the expression of vascular endothelial growth factor (VEFG), and the numbers of hair follicles in growth phase after oral administration. A total of 12 C57BL/6 mice were divided into two groups: control group and treatment group BT. BT was administered orally as an extract at a volume of 0.6 g/kg. The control group was treated with distilled water. Each group was treated once a day for 12 consecutive days. To observe the expression of VEGF distribution, the number of hair follicles and the hair coverage were examined on days 4, 8, and 12. By comparing the treatment group and control group, we found that VEGF in the BT group on day 8 presented with a higher area percentage than the control group (p value = 0.003). Hair follicle counting results showed that the BT group was significantly higher than the control group on day 8 (p value = 0.031). Furthermore, hair coverage was shown to be significantly increased in the treatment group BT on day 8 (p value = 0.013). Taken together, these results suggest that Chinese medicine (BT) possesses the potential effect of promoting hair growth through VEGF expression. VEGF is considered the most important mediator for the process of angiogenesis involved in hair growth development.

Enzymatic degradation of ginkgolic acids by laccase immobilized on core/shell Fe3O4/nylon composite nanoparticles using novel coaxial electrospraying process.

Enzyme immobilization can increase enzyme reusability to reduce cost of industrial production. Ginkgo biloba leaf extract is commonly used for medical purposes, but it contains ginkgolic acid, which has negative effects on human health. Here, we report a novel approach to solve the problem by degrading the ginkgolic acid with immobilized-laccase, where core/shell composite nanoparticles prepared by coaxial electrospraying might be first applied to enzyme immobilization. The core/shell Fe3O4/nylon 6,6 composite nanoparticles (FNCNs) were prepared using one-step coaxial electrospraying and can be simply recovered by magnetic force. The glutaraldehyde-treated FNCNs (FNGCNs) were used to immobilize laccase. As a result, thermal stability of the free laccase was significantly improved in the range of 60-90 °C after immobilization. The laccase-immobilized FNGCNs (L-FNGCNs) were applied to degrade the ginkgolic acids, and the rate constants (k) and times (τ50) were ~0.02 min-1 and lower than 39 min, respectively, showing good catalytic performance. Furthermore, the L-FNGCNs exhibited a relative activity higher than 0.5 after being stored for 21 days or reused for 5 cycles, showing good storage stability and reusability. Therefore, the FNGCNs carrier was a promising enzyme immobilization system and its further development and applications were of interest.

Bioactive compounds with anti-oxidative and anti-inflammatory activities of hop extracts.

The aim of this study is to simultaneously evaluate anti-oxidative and anti-inflammatory activities of the hop extracts by different solvents. Hop water extract (HWE) and hop ethanol extracts (HEEs) were prepared by extracting hop pellets with hot water at 90 °C and ethanol solutions (55%, 75%, and 95%), respectively. Bioactive compound such as α-acid, ß-acid, total phenolic, and total flavonoid contents were determined. All the HEEs showed higher anti-oxidative activities than the HWEs. The HEEs showing the highest anti-oxidative activities are different in the experiments with different free radicals. For anti-inflammatory activities, both the HWE and HEEs decreased NO productions. HWE decreased TNF-α and IL-6 secretion but showed no effect on IL-1ß, while HEEs decreased IL-1ß and IL-6 secretion but increased TNF-α secretion. Except for TNF-α secretion, the HEEs showed higher anti-inflammatory activities than the HWE. Future work is to explore the possible mechanism to improve the ethanol extraction procedure.

Assessment of optic nerve and optic tract alterations in patients with orbital space-occupying lesions using probabilistic diffusion tractography.

AIM: To investigate the diffusion changes in both the optic nerve and optic tract in orbital space-occupying lesion patients with decreased visual acuity, and its clinical significance using probabilistic diffusion tractography (PDT). METHODS: Twenty patients with orbital space-occupying lesions and 25 age- and gender-matched healthy persons were included. All patients and controls underwent routine orbital magnetic resonance imaging and diffusion tensor imaging (DTI), using a 3.0T magnetic resonance scanner (Trio Tim Siemens). After the image data were preprocessed, each DTI parameters of the optic nerve and optic tract was obtained by PDT, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD). The asymmetry index (AI) of each parameter was calculated. Compared the parameters of the affected side optic nerve and ipsilateral optic tract with the contralateral side by paired sample t-test; compared AI of parameters of optic nerve and optic tract between the patient group and the control group by independent sample t-test. Patients were divided into three subgroups according to the low vision grade standard of WHO, compared the FA and AI of FA between the three subgroups by single factor variance analysis. RESULTS: The affected side optic nerve presented significantly decreased FA, increased MD, AD, and RD values compared to the unaffected side (P<0.05). The AI of FA, MD, AD, and RD of optic nerve in the patients was significantly higher than that of the controls (P<0.05). The comparison results of the optic tract showed that there was no significant difference between the patient group and control group in terms of the bilateral optic tracts in patients (P>0.05). The AIs of the FA value of the optic nerve in the eyesight <0.1 subgroup was significantly higher than that in the other groups (P<0.05). CONCLUSION: FA, MD, AD, and RD of the affected side optic nerve of the orbital space-occupying lesions have significantly changed, the FA value is the most sensitive. The PDT could be a useful tool to provide valid quantitative markers of optic nerve injuries and evaluate the severity of orbital diseases, which other examinations cannot be acquired.

Novel pH-responsive granules with tunable volumes from oxidized corn starches.

Novel pH-responsive granules with tunable volume from oxidized starch granules were prepared from waxy and normal corn starches using 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation and pregelatinization. Conditions of both oxidation and pregelatinization were designed on the basis of maintaining intact granules' morphology. Carboxylate groups at C6 in anhydroglucose of the oxidized starch acting as pH-responsivity controllers were introduced to by TEMPO/NaClO/NaClO2 system at pH 6.8 to achieve degrees of oxidation of 9-10%. Formation of the carboxylate groups was confirmed by Fourier transform infrared spectroscopy and thermogravimetric analysis. The TEMPO-oxidized waxy and normal corn starch granules (TWSG and TNSG) were pregelatinized at 65 °C for 5 and 16 min, respectively, to provide desirable swelling capacity of granules. The anionic pregelatinized TWSG and TNSG show swelling ratios of 15.6 and 11.7 at pH 2 and 31.6 and 25.0 at pH 7, respectively, exhibiting good pH-responsivity and potentials for active compounds delivery applications.

TEMPO-Oxidized Bacterial Cellulose Pellicle with Silver Nanoparticles for Wound Dressing.

Biocompatible bacterial cellulose pellicle (BCP) is a candidate for biomedical material such as wound dressing. However, due to lack of antibacterial activity, to grant BCP with the property is crucial for its biomedical application. In the present study, BCP was modified by 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation using TEMPO/NaClO/NaBr system at pH 10 to form TEMPO-oxidized BCP (TOBCP) with anionic C6 carboxylate groups. The TOBCP was subsequently ion-exchanged in AgNO3 solution and silver nanoparticles (AgNP) with diameter of ∼16.5 nm were in situ synthesized on TOBC nanofiber surfaces by thermal reduction without using a reducing agent. Field emission scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectra, Fourier transform infrared spectroscopy, and thermogravimetric analysis were carried out to confirm morphology and structure of the pellicles with AgNP. The AgNP continuously released Ag+ with a rate of 12.2%/day at 37 °C in 3 days. The TOBCP/AgNP exhibited high biocompatibility according to the result of in vitro cytotoxicity test (cell viability >95% after 48 h of incubation) and showed significant antibacterial activities of 100% and 99.2% against E. coli and S. aureus, respectively. Hence, the highly biocompatible and highly antibacterial TOBCP/AgNP prepared in the present study is a promising candidate for wound dressing.

Increase in the water contact angle of composite film surfaces caused by the assembly of hydrophilic nanocellulose fibrils and nanoclay platelets.

Controlling the assembly modes of different crystalline nanoparticles in composites is important for the expression of specific characteristics of the assembled structures. We report a unique procedure for increasing water contact angles (CAs) of composite film surfaces via the assembly of two different hydrophilic components, nanocellulose fibrils and nanoclay platelets. The nanocellulose fibrils and nanoclay platelets used have ionic groups on their surfaces in high densities (∼1 mmol g(-1)) and have no hydrophobic surface. The increase in the CA of the nanocellulose/nanoclay composite films was thus analyzed on the basis of the air area fractions of their nanostructured surfaces following Cassie's law. The air area fractions were geographically estimated from the atomic force microscopy height profiles of the composite film surfaces. The CAs of the composite film surfaces were found to be well described by Cassie's law. Interestingly, the composite films consisting of two hydrophilic nanoelements with different shapes exhibited CAs larger than those of the individual neat films.

Cellulose-clay layered nanocomposite films fabricated from aqueous cellulose/LiOH/urea solution.

Transparent and flexible cellulose-clay (montmorillonite, MTM) nanocomposite films are prepared from cellulose/LiOH/urea solutions. The results show that the composites possess intercalated nanolayered structures. Almost no Na ions are present in MTM, probably because they are substituted by Li ions. The nanocomposite films possess high mechanical strength and gas barrier properties, and lower coefficients of thermal expansion than those of the original cellulose film. In particular, the composite film of 85% cellulose and 15% MTM has the highest tensile strength and Young's modulus 161 and 180% greater than those of the 100% cellulose film, and coefficient of thermal expansion and oxygen permeability at 50-75% RH decrease to 60 and 42-33%, respectively. Moreover, the initial hydrophilic nature of cellulose film changes to somewhat hydrophobic through incorporation of hydrophilic MTM platelets. This is probably because the orientation of cellulose chains on the film surface changes by the formation of numerous hydrogen bonds between cellulose molecules and MTM platelets.

Highly tough and transparent layered composites of nanocellulose and synthetic silicate.

A highly tough and transparent film material was prepared from synthetic saponite (SPN) nanoplatelets of low aspect ratios and nanofibrillar cellulose. The nanofibrillar cellulose was chemically modified by topological surface oxidation using 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO) as a catalyst. Both synthetic SPN nanoplatelets and TEMPO-oxidized cellulose nanofibrils (TOCNs) have abundant negative charges in high densities on their surfaces and are dispersed in water at the individual nanoelement level. Layered nanocomposite structures of the SPN nanoplatelets and TOCNs were formed through a simple cast-drying process of the mixed aqueous dispersions. The TOCN/SPN composites with 0-50% w/w SPN content were optically transparent. Mechanical properties of the TOCN/SPN composites varied depending on the SPN content. The composite with 10% w/w SPN content (5.6% volume fraction) exhibited characteristic mechanical properties: Young's modulus of 14 GPa, tensile strength of 420 MPa, and strain-to-failure of 10%. The work of fracture of the composites increased from 4 to 30 MJ m(-3)- or by more than 700%--as the SPN content was increased from 0 to 10% w/w. This surprising improvement in toughness was interpreted based on a model for fracture of polymer composites reinforced with low-aspect-ratio platelets.

Ultrastrong and high gas-barrier nanocellulose/clay-layered composites.

Nanocellulose/montmorillonite (MTM) composite films were prepared from 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-oxidized cellulose nanofibrils (TOCNs) with an aspect ratio of >200 dispersed in water with MTM nanoplatelets. The composite films were transparent and flexible and showed ultrahigh mechanical and oxygen barrier properties through the nanolayered structures, which were formed by compositing the anionic MTM nanoplatelet filler in anionic and highly crystalline TOCN matrix. A composite film with 5% MTM content had Young's modulus 18 GPa, tensile strength 509 MPa, work of fracture of 25.6 MJ m(-3), and oxygen permeability 0.006 mL µm m(-2) day(-1) kPa(-1) at 0% relative humidity, respectively, despite having a low density of 1.99 g cm(-3). As the MTM content in the TOCN/MTM composites was increased to 50%, light transmittance, tensile strength, and elongation at break decreased, while Young's modulus was almost unchanged and oxygen barrier property was further improved to 0.0008 mL µm m(-2) day(-1) kPa(-1).